Urban sprawl and its economic, social, and environmental consequences are central issues for approaching more sustainable forms of life and production. This review provides a broad theoretical exploration of the main features of urban sprawl but also of sustainable urban policies in Western Europe and North America. Urban sprawl can be observed in both continents, as the search for higher standards of economic, social, and environmental sustainability is also an essential feature of urban governance in the last years. Urban sprawl has been slightly weaker in Western Europe, as its are cities generally more compact. Moreover, in Western Europe, urban sprawl has sometimes been confronted with ex-ante preventive policies. However, in North America, urban sprawl from the 1950s has been an essential element of the social ordering and, thus, of the American way of life. In both cases, urban sprawl has generated successive rounds of accumulation of built capital, which is currently managed in sustainable ways essentially through ex-post and palliative measures, that is, trying to “sustain what is unsustainable”. In other words, the idea is to make urban sprawl more sustainable but without altering its main morphological elements.

Polycultured agrarian systems in Ecuadorian Amazonia (also called chakras or swollen gardens) are characterised by a market-oriented crop for the generation of monetary income, for example, cocoa, other agricultural products (e.g., banana and cassava), and livestock for family farm consumption. Moreover, a chakra is an outstanding example of agroforestry production, in which ecological, social and economic elements co-evolve from a set of close and strong connections. In this context, the conservation and transformation of their biological subsystems can be understood as the result of complex interactions between anthropogenic and non-anthropogenic factors. In turn, such interactions are essential to provide food and monetary income to the indigenous community. Relevant agency capabilities exist that could cause an agroforestry system to take a different path of co-evolution, that is, towards greater or lesser sustainability associated with different levels of complexity. In conclusion, chakras have key ecological features that can mitigate the impact of human population growth in Amazonia. Additionally, chakras have their own processes of social self-regulation which enhance the possibilities of adaptation of Kichwa communities to changing environmental conditions, being essential elements in local food sovereignty, equitable gender relations and the respect of ancestral wisdom.

In recent decades, urban processes have experienced deep transformations. One of them has been the growing importance of urban sprawl. This article reviews its main features and the policies related to the paradigm of sustainability in three Latin American Megalopolises: Mexico City, Lima, and Santiago de Chile. For this purpose, we have carried out an extensive compilation of the existing academic literature. Urban sprawl in those cities cannot be understood without considering the rising housing needs of popular classes, usually addressed through the sequence settlement-parceling-building-urbanization. Simultaneously high-income groups tend to create separated and gated commodities and there is increasing spatial mobility of the middle classes. Those processes tend to generate highly segregated and increasingly patched metropolitan areas. Sustainability is framed on models of urban governance based on ecological modernization. In this context, three main sustainable policies are analyzed: water supply, green areas provision, and transport. Conclusions stress: (1) Deep changes experienced and the path-dependent element observed in the social construction of sustainability (2) Consolidation of a model of socially segregated and ecologically differentiated urban polycentrism (3) Relevance of the different megalopolises as niches of experimentation and innovation in the construction of specific forms of sustainable transition.